Emerald ash borer discovered in Mass.

HARDWICK 
Yet another destructive insect pest has arrived on the state’s doorstep, discovered in a beetle trap not too long ago in the Berkshires town of Dalton.

But unlike the Asian longhorned beetle that feeds on more than a dozen different hardwoods, taking as long as five years to kill a tree, the Emerald ash borer targets only ash trees and can kill a white or green ash in two to three years, according to Ken Gooch, forest health program director for the state Department of Conservation and Recreation.

The good news is that to date, only the one beetle has been found; based on the insect’s life cycle, will remain dormant as larvae within a tree until late spring.

The state agency is taking down ash trees in the immediate area of the trap where the adult beetle was discovered to determine the extent of the infestation.

Biological controls may slow the spread. Another method is the creation of “trap” trees to confine the ash borer larva to the layer of the tree that transports nutrients.

Mr. Gooch said biological controls that have been successful in curbing the beetle include Spathius agrili, a non-stinging wasp that lays eggs through the bark onto beetle larva, paralyzing and ultimately killing them.

“At this point, there is no quarantine. We have a two-mile radius grid from where the beetle was found in the trap and we are in the process of cutting trees, stripping bark and looking for signs of ash borer infestation,” Mr. Gooch said.

Ash from quarantined regions can be used commercially if sterilized in kilns. Jason Ayer, manager of Hardwick Kilns, said the company has signed a compliance agreement with the U.S. Department of Agriculture that allows it to process timber from quarantined regions.

The ash borer beetle was first discovered in Michigan in 2002, a likely import with packing materials from China .

“As the Emerald ash borer spread from the Midwest, coming closer to Massachusetts, it became more of an issue for us. While we will process lumber from anywhere in the world, for the most part we process timber from the New England states, New York and Pennsylvania because of trucking costs,” the kiln manager said.

The quarantine of ash in Pennsylvania and New York had an immediate impact on the kiln’s business.

“In order to receive lumber during the ‘no-fly period’ of the beetle’s life cycle — Oct. 1 through April 31 — I had to sign a compliance agreement with the USDA. Essentially what that did was put rules in place as to how we would treat that wood once it arrived here,” Mr. Ayer explained.

In fact, he said, the kiln already was using methods that exceeded what the federal agency required.

The manager said kiln sterilization requires a core temperature of 140 degrees, a moisture content of 13.8 percent, and, depending on the thickness of the wood, maintaining those conditions for a specific number of hours.

“Meeting the requirement was easy, because here we dry our lumber here to 6 to 8 percent moisture at a temperature of 150 to 155 degrees for a period of four to five days,” Mr. Ayer said.

He said ash represents about 20 percent of the Hardwick Kiln’s business, about 1.5 million to 2 million board feet a year.

Despite biological controls and the slowing of the progress of the Emerald ash borer beyond the Berkshires, Mr. Ayer said he’s not all that optimistic the pest can be contained.

“The quarantine is about slowing the beetle down, because it’s not going to stop it from spreading. I believe it’s already here and in our lifetime, the ash trees will be gone. Fortunately there will be a future generation of ash that will survive because, unlike the chestnut blight, a fungus that kills young American chestnuts, once the mature ash trees are gone, the ash borer will be gone as well,” he said.

He said he’s worked cooperatively with state officials on methods of killing the beetle.

“Fumigation is one method, but it’s cost prohibitive. Removal of a half inch of wood once the bark has been stripped is another method, but that too is prohibitive. No sawmill that I know will do that because it represents about 10 percent of the product,” the manager explained.

That leaves kiln sterilization and heat treating as the remaining options.

Processing the timber so that it can be used in making furniture, flooring and other products is the only option that makes the most of the resource, he said.

Ash represents about 7 percent to 8 percent of the mix of hardwoods across Massachusetts, and 80 percent of the state’s white ash and green ash trees are in Berkshire County, according to the state.